title: Evidence for supernova injection into the solar nebula and the decoupling of r-process nucleosynthesis.
abstract: The isotopic composition of our Solar System reflects the blending of materials derived from numerous past nucleosynthetic events, each characterized by a distinct isotopic signature. We show that the isotopic compositions of elements spanning a large mass range in the earliest formed solids in our Solar System, calcium-aluminum-rich inclusions (CAIs), are uniform, and yet distinct from the average Solar System composition. Relative to younger objects in the Solar System, CAIs contain positive r-process anomalies in isotopes A < 140 and negative r-process anomalies in isotopes A > 140. This fundamental difference in the isotopic character of CAIs around mass 140 necessitates (i) the existence of multiple sources for r-process nucleosynthesis and (ii) the injection of supernova material into a reservoir untapped by CAIs. A scenario of late supernova injection into the protoplanetary disk is consistent with formation of our Solar System in an active star-forming region of the galaxy.
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, CA 94550.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Brennecka
authors.forename: Lars E
authors.initials: LE
authors.lastname: Borg
authors.forename: Meenakshi
authors.initials: M
authors.lastname: Wadhwa
mesh_terms: D000535:Aluminum / Q000737:chemistry; D001464:Barium / Q000737:chemistry; D002118:Calcium / Q000737:chemistry; D005118:Extraterrestrial Environment / Q000737:chemistry*; D007554:Isotopes / Q000032:analysis*; D019110:Meteoroids; D008982:Molybdenum / Q000737:chemistry; D009354:Neodymium / Q000737:chemistry; D012493:Samarium / Q000737:chemistry; D016082:Solar System / Q000737:chemistry*; D013324:Strontium / Q000737:chemistry; D013997:Time Factors
chemical_list: D007554:Isotopes; D001464:Barium; D009354:Neodymium; D012493:Samarium; D008982:Molybdenum; D000535:Aluminum; D002118:Calcium; D013324:Strontium
keywords: H-Event; early Solar System; isotopic anomalies; nebular disk